In relation to the production or extraction of for example dissolved, suspended or chemically bonded substances, such as uranium or other metal compounds, from water, an apparatus and a process have been disclosed in the above-mentioned copending application (German Offenlegungsschrift No. 25 50 751) wherein the water, which is flowing in a substantially horizontal direction in relation to the apparatus, is caused to flow substantially in a vertical direction, through a fluidized bed of adsorber particles which bond the substances. In this process, a plurality of fluidized beds are disposed in projecting cantilever arms carried by a carrier member, with the water flowing over the arms and also therethrough. In this arrangement, the cantilever arms have adjustable guide surfaces for influencing and guiding the flow of water.
Since for example seawater but also other water contains the substances which are to be considered for extraction, only in an extremely diluted form, for example with a metric ton of seawater containing only about 3 mg of uranium, in order to produce such substances from water it is necessary to pass extremely large amounts of water through the apparatus. Thus, in order to produce uranium in a quantity which is economically attractive, it is necessary for water to be passed through the apparatus, in an amount which is of the order of magnitude of thousands of millions of tons. The specific nuclear energy content of water in the sea is thus very low. This means that only a very small fraction of this energy can be used for the entire production process, per unit of water to be treated, in order for the energy balance sheet to show a positive figure at the end of the operation.
Accordingly, for economically producing for example uranium, using the process referred to above, it is necessary to take the energy which is required for fluidizing the bed of adsorber particles, from other energy sources present in the sea. The natural sea currents or possibly also the current in a river offer themselves as possibilities in this respect. It has been found however that the kinetic energy in currents of this kind is at such a low level that it is not possible to utilize this energy for maintaining the above-mentioned fluidized bed, without special measures being taken, such as the guide surfaces in the above-mentioned process. However, these guide means are often not sufficient to achieve the required effect.